The present invention relates to accelerators for light sensitive diazonium compounds and to presensitized reproduction materials such as proofing films, contact films and other nonprinting films, having enhanced photosensitivity and increased speed.
Pre-sensitized reproduction materials such as these used for contact exposure processes generally comprise a film base over which is applied a photosensitive coating composition. The film base may be a flexible sheet such as paper, plastic, metal-coated plastic or a combination of plastic and paper. Plastics used for such purposes may consist of polyester, polystyrene, polypropylene, cellulose acetate, and the like. The film used may optionally have applied a coating of an adhesion promoter which will provide improved anchorage for the subsequently applied light sensitive coating. Most commonly used adhesion promoters are, but not restricted to, silane and siloxane compounds and are well known in the art.
Diazonium compounds most commonly employed in the preparation of light sensitive compositions suitable for proofing film, contact film applications or photoresist applications may be characterized by the generic structure A--N.sub.2.sup.+ X.sup.-, wherein A is an aromatic or heterocyclic residue and X is the anion of an acid.
Specific examples of light sensitive diazonium materials useful as aforementioned include higher molecular weight compositions obtained, for example, by the condensation of certain aromatic diazonium salts in an acid condensation medium with active carbonyl compounds such as formaldehyde, as disclosed for example in U.S. Pat. Nos. 2,063,631 and 2,667,415.
More recently, improved diazonium materials within the above generic formula have been developed which are faster, more adherable to support materials and exhibit lessened sensitivity to moisture. These include the reaction products having the structures resulting from the condensation of the compounds of Formula I, as follows:
FORMULA I: At least one diazonium salt having the structure: ##STR1## wherein Z is the benzene ring; wherein X is as defined above; and,
wherein R.sub.1 is selected from the group consisting of H, an alkoxy group having from 1 to 4 carbon atoms, and a 2-hydroxy-ethoxy group, PA1 condensed with at least one compound of the general structure: EQU R(--CH.sub.2 --OR.sub.2).sub.n PA1 wherein n is an integer from 1 to 4; PA1 wherein R is a residue produced by the splitting off of n hydrogen atoms from a diphenyl ether; and, PA1 wherein R.sub.2 is an alkyl group with 1 to 4 carbon atoms, PA1 said condensation product containing, on the average, about 0.25 to about 0.75 units derived from R(--CH.sub.2 --OR.sub.2).sub.n per units of diazo group. Such materials are disclosed in U.S. Pat. No. 3,679,419, incorporated herein by reference. PA1 R.sub.1 ' is an arylene group of the benzene or naphthalene series PA1 R.sub.2 is a phenylene group PA1 R.sub.3 is a single bond or one of the groups EQU --(CH.sub.2).sub.q --NR.sub.4 -- EQU --O--(CH.sub.2).sub.r --NR.sub.4 -- EQU --S--(CH.sub.2).sub.r --NR.sub.4 -- EQU --S--CH.sub.2 --CO--NR.sub.4 -- EQU --O--R.sub.5 --O-- EQU --O-- EQU --S-- PA1 the left-hand free valence of the specified groups is attached to R.sub.1 and the right-hand free valence is attached to R.sub.2, PA1 q is a number from 0 to 5 PA1 r is a number from 2 to 5 PA1 R.sub.4 is selected from the group consisting of hydrogen, alkyl with 1 to 5 carbon atoms, aralkyl with 7 to 12 carbon atoms, and aryl with 6 to 12 carbon atoms, R.sub.5 is an arylene group having 6 to 12 carbon atoms PA1 R.sub.5 is an arylene group having 6 to 12 carbon atoms PA1 Y is one of the groups EQU --NH--, and --O-- PA1 X is an anion PA1 P is a number from 1 to 3 PA1 E is a residue obtain by splitting of mH atoms from a compound free of diazonium groups selected from the group consisting of aromatic amines, phenols, thiophenols, phenol ethers, aromatic thioethers, aromatic heterocyclic compounds, aromatic hydrocarbons and organic acid amides, PA1 R.sub.a is selected from the group consisting of hydrogen and phenyl, PA1 R.sub.b is selected from the group consisting of hydrogen and alkyl and acyl groups having 1 to 4 carbon atoms, and a phenyl group, and PA1 m is an integer from 1 to 10, PA1 are reacted in a strongly acid condensation medium and under condensation conditions sufficient to produce a polycondensation product of an aromatic diazonium compound containing on the average, about 0.1 to 50 B.sub.1 units per unit of A--N.sub.2 X. PA1 R.sub.2 is a phenylene group PA1 R.sub.3 is a single bond or one of the groups EQU --(CH.sub.2).sub.q --NR.sub.4 -- EQU --O--(CH.sub.2).sub.r --NR.sub.4 -- EQU --S--(CH.sub.2).sub.r --NR.sub.4 -- EQU --S--CH.sub.2 --CO--NR.sub.4 -- EQU --O--R.sub.5 --O-- EQU --O-- EQU --S-- PA1 the left-hand free valence of the specified groups is attached to R.sub.1 and the right-hand free valence is attached to R.sub.2, PA1 q is a number from 0 to 5 PA1 r is a number from 2 to 5 PA1 R.sub.4 is selected from the group consisting of hydrogen, alkyl with 1 to 5 carbon atoms, aralkyl with 7 to 12 carbon atoms, and aryl with 6 to 12 atoms, PA1 R.sub.5 is an arylene group having 6 to 12 carbon atoms PA1 --Y-- is one of the groups EQU --NH--, and --O-- PA1 X is an anion of the diazonium compound, and PA1 P is a number from 1 to 3, and PA1 B is a radical of a compound selected from the group consisting of aromatic amines, phenols, thiophenols, phenol ethers, aromatic thioethers, aromatic heterocyclic compounds, aromatic hydrocarbons and organic acid amides, in which the aromatic nuclei are unsubstituted or substituted by at least one substituent activating condensation and selected from the group consisting of --NR.sub.7 R.sub.8, --N(R.sub.8).sub.2, --OR.sub.7, --OR.sub.8, --R.sub.8, and --SR.sub.8, PA1 R.sub.7 is --H, --CO--alkyl, --CO--aryl, --SO.sub.2 --alkyl, --SO.sub.2 --aryl, --CONH.sub.2, or CSNH.sub.2, and PA1 R.sub.8 --H, alkyl, aryl or aralkyl, the alkyl groups having 1 to 10, the aryl groups 6 to 20, and the aralkyl groups 7 to 20 carbon atoms, which diazonium compound contains, on the average, about 0.01 to 50 B units per units of A--N.sub.2 X. PA1 m is 1 to about 9; PA1 Y is selected from the group consisting of --CH.sub.2 -- and --CH.sub.2 OCH.sub.2 --; and, PA1 T is the same as R when Y is --CH.sub.2 -- and is hydrogen when Y is --CH.sub.2 --O--CH.sub.2 --, PA1 R' is selected from the group consisting of phenyl and C-1 to C-4 alkyl substituted phenyl; PA1 K is selected from the group consisting of ##STR7## or is absent; P and P.sub.1 may be the same or different and are selected from the group consisting of C.sub.1 to C.sub.4 alkyl, methoxy, ethoxy, butoxy, and H; and, X is an anion.
Other diazonium compounds include the polycondensation products having the structures resulting from the condensation of the compounds of Formula II, as follows:
FORMULA II: At least one A--N.sub.2.sup.+X.sup.- compound as discussed above, condensed with at least one compound of the structure EQU E(CHR.sub.a --OR.sub.b).sub.m
as defined on column 1, lines 15-72 and column 2, lines 1-5 of U.S. Pat. No. 3,849,392, incorporated herein by reference.
The referenced patent relates to a process for the preparation of polycondensation products of aromatic diazonium compounds, useful as light-sensitive coatings, particularly in the preparation of printing plates and the like, in which at least one A--N.sub.2 X compound and at least one B.sub.1 compound of the formula: EQU E(--CHR.sub.a -OR.sub.b).sub.m
in which: A--N.sub.2 X is a radical of a compound selected from the group consisting of a compound of the formulae: ##STR2## wherein R.sub.1 is an aryl group of the benzene or naphthalene series
or EQU --CO--NR.sub.4 --
wherein
Still other diazonium materials include those materials having repeating units of the structures resulting from the condensation of the compounds of Formula III, as follows:
FORMULA III: At least one A--N.sub.2.sup.+ X.sup.- compound as discussed above, condensed with at least one compound of the structure B, as defined on column 93, lines 65-70 and column 94, lines 1-58 of U.S. Pat. No. 3,867,147, incorporated herein by reference.
The referenced patent describes an aromatic diazonium compound comprising repeating units of each of the general types A--N.sub.2 X and B which are linked by methylene groups, in which A--N.sub.2 X is a radical of a compound of one of the general formulae ##STR3## wherein R.sub.1 is an arylene group of the benzene or naphthalene series
or EQU --CO--NR.sub.4 --
wherein
wherein
Yet another category of extremely fast light sensitive diazos are those disclosed in copending application Ser. No. 359,335, filed in the United States Patent Office of even date herewith, which is a continuation-in-part of Ser. No. 06/245,837, filed in the United States Patent Office on Mar. 20, 1981, by John E. Walls, entitled "Reproduction Materials Based on Light Sensitive Diazo Compounds", both incorporated herein by reference.
These materials may be characterized as the condensation products of the compounds of Formula IV, as follows:
FORMULA IV: The condensation product of oligomers having the structure: ##STR4## wherein: R is selected from the group consisting of ##STR5## n is an integer from 0 to 3; M is an aromatic radical of one or more compounds selected from the group consisting of aromatic hydrocarbons, diaryl ethers, diaryl sulfides, diaryl amines, diaryl sulfones, diaryl ketones and diaryl diketones;
condensed with diazonium salts having the structure: ##STR6## wherein: Z is the benzene ring;
Whereas recently developed, faster diazos offer many advantages in terms of speed and quality which render them extremely suitable in applications requiring low energy light exposure, including laser exposure applications, the demand, nonetheless, for even higher speed compositions persists. Although many of the less sensitive low molecular weight diazos exhibit acceptable speeds and photosensitivity for many applications, sensitized proofing films and the like coated with the accelerated compositions of the present invention offer even faster, more efficient and more profitable production capabilities.